Adhesive sheet materials such as wallpaper, shelving paper, posters, note pads, labels, and the like, which are to be applied to a variety of surfaces for decorative, or protective purposes, have traditionally been prepared by coating a base sheet with a water-activated or water-based adhesive, e.g., wallpaper paste.
Sheet materials prepared with such adhesives suffer from a variety of defects which render them particularly unsuited for use by homeowners or other "do-it-yourselfers". In the first place, such sheet materials are generally very messy and time consuming to apply. The homeowner is either required to prepare a messy, wet paste which is brushed onto the sheet material, or wet out large sheets coated with a water-activated adhesive, which are cumbersome and difficult to handle.
It is also difficult, if not practically impossible to remove such sheet materials from the adhered-to surface after the adhesive has dried, in order to redecorate or return the surface to its original condition. It is usually necessary to thoroughly wet the sheeting and then scrape it from the surface.
More recently, adhesive sheet materials have been prepared by coating a base sheet with a pressure sensitive adhesive. As known in the art, the term "pressure sensitive" is used to describe those synthetic and natural resins having a viscoelastic property termed "tack". Generally, pressure sensitive adhesives need not undergo a phase change in order to bond materials together. See, F. Keimel, Adhesives, vol. 22 Encyclopedia of Chemical Technology 3rd ed. (Kirk-Othmer 1983) p. 490, incorporated by reference herein.
The use of pressure sensitive adhesives is desirable because there is no need for the homeowner to apply a water-based adhesive or wet a previously applied water-activated adhesive. However, prior proposals for providing a sheet material which is coated with a pressure sensitive adhesive have the following disadvantages, among others. It is often difficult to position or reposition these adhesive-coated sheet materials during application to avoid the occurrence of bubbles or wrinkles, and to properly match any designs or patterns.
Moreover, it is difficult to remove the adhesive-coated sheet material from the surface after it has been in place for a period of time without leaving an adhesive residue on the surface, or otherwise damaging or marring the surface. Thus, such sheet materials are unsuited for use by renters or other consumers who are required to return the wall or other surface to its original coddition. Additionally, because such sheet materials are difficult to remove, homeowners have limited freedom to redecorate their surroundings.
Attempts to produce a firmly adhesive sheet material which can be easily positioned or repositioned during the application period, by using pressure sensitive adhesives, have so far failed to provide a commercially viable sheet material which does not require wetting during application and maintains its adherable, yet readily removable and repositionable nature with respect to a wide variety of surfaces over an extended period of time.